There is a significant historical issue here where, as far as I can see has
never been properly addressed. If I am wrong in this no doubt some one
will tell me where to look. What is the composition of fireclay and when
did it begin to be used?
The need for a good refractory only arises where there are very hot
materials to be contained. Early blast furnace linings were apparently
usually of stone, for example 17th century leases of Cradley Furnace,
(Staffs.) provided that the tenant could get two hearths from Himley
(perhaps five miles away). At Coalbrookdale in the 1720s materials used
included hearth stones and inwall stones from Highley (Salop.) and
Stourbridge brick and Stourbridge clay, meaning is fireclay. Precisely
how these were being used is not wholly apparent. The stones were
evidently for relining blast furnace hearths since they were bought about
the time that a furnace was out of blast. I am not sure whether there is a
correlation between the purchase of Stourbridge brick and clay or not.
Stourbridge clay was first used in the glass industry and the early history
of clay mining is to be found in books on glass. However when it began to
be used in metal smelting industries and foundries does not seem to have
been determined.
Peter King
----- Original Message -----
From: Skip Williams <[log in to unmask]>
To: <[log in to unmask]>
Sent: 31 October 2000 22:51
Subject: Re: refractory clay
> Irene,
> During the manufacture of refractory materials the ingredients are
> selected to achieve certain chemical and physical properties in the
> finished material. Among the variables that can be controlled for are:
> thermal expansion, resistance to corrosive environments, strength, and
> toughness (resistance to the abrasive action of the materials that will
> be in contact with the refractory during its operating life)
>
> In addition to the variation of the chemical composition mentioned by
> Killick and Young, the raw materials may also be processed for desired
> physical characteristics. Selecting by grain size is a prime example
> (larger grains being more slow to react). But we must also include in
> this category, any materials that have been previously fired to 'grow'
> certain mineral species that are highly refractory, ground up, and added
> to the mix.
>
> Thirdly, conditions during sintering (if a the product is a ceramic
> shape), or during use (if the product is a castable refractory), will
> influence the strength, refractoriness, and heat transfer
> characteristics of these materials
>
> A little experience is worth a thousand calculations!
>
>
> for more information try:
> Grimshaw, Rex W The chemistry and physics of clays and allied ceramic
> materials, by Rex W. Grimshaw, New York, Wiley-Interscience [1971] 4th
> ed. rev
>
> Skip Williams
>
>
> >>> [log in to unmask] 10/31/00 11:57AM >>>
> Dear all,
> could anyone please tell me: what properties make a clay refractory?
>
> Many thanks, Irene
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